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Wall lizards display conspicuous signals to conspecifics and reduce detection by avian predators.


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Authors

Marshall, Kate LA 
Stevens, Martin 

Abstract

Visual signals are often under conflicting selection to be hidden from predators while being conspicuous to mates and rivals. Here, we investigated whether 3 different island populations of Aegean wall lizards (Podarcis erhardii) with variable coloration among diverse island habitats exhibit simultaneous camouflage and sexual signals. We examined whether signals appear better tuned to conspecific vision as opposed to that of avian predators, and whether background-matching camouflage and sexual signals are partitioned to specific body regions. This could facilitate both covert sexual signaling and camouflage according to the viewing perspectives of predators and conspecifics. We found that lizards typically appeared twice as conspicuous to conspecifics than to avian predators against the same visual background, largely due to lizards' enhanced sensitivity to ultraviolet, suggesting that P. erhardii signals are tuned to conspecific vision to reduce detection by predators. Males were more conspicuous than females to both predators and conspecifics. In 2 populations, male backs were relatively more camouflaged to predators compared to signaling flanks, whereas in females, exposed and concealed surfaces were camouflaged to predators and generally did not differ in background matching. These findings indicate that lizard coloration evolves under the competing demands of natural and sexual selection to promote signals that are visible to conspecifics while being less perceptible to avian predators. They also elucidate how interactions between natural and sexual selection influence signal detectability and partitioning to different body regions, highlighting the importance of considering receiver vision, viewing perspectives, and signaling environments in studies of signal evolution.

Description

This is the final published version. It's also available from Oxford Journals at http://beheco.oxfordjournals.org/content/early/2014/07/27/beheco.aru126.short?rss=1.

Keywords

camouflage, color variation, communication, signal partitioning, trade-offs, vision.

Journal Title

Behav Ecol

Conference Name

Journal ISSN

1045-2249
1465-7279

Volume Title

Publisher

Oxford University Press (OUP)
Sponsorship
This work was supported by a Biotechnology and Biological Sciences Research Council studentship and Magdalene College, Cambridge (K.L.A.M), and a Biotechnology and Biological Sciences Research Council and David Philips Research Fellowship (grant number BB/G022887/1) to M.S.